Apoptosis, Necrosis, and Necroptosis in the Gut and Intestinal Homeostasis

Dihydroartemisinin attenuates acetic acid-induced ulcerative colitis in rats: Suppression of inflammation and modulation of NFκβ/TNF-α/RIPK1-mediated necroptosis and apoptosis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by the overproduction of reactive oxygen species (ROS) and the release of inflammatory mediators. Dihydroartemisinin (DHA) is a semi-synthetic active metabolite of artemisinin that has anti-inflammatory, antioxidant, and anti-fibrotic properties.

OBJECTIVE

This study aimed to assess the therapeutic benefits of DHA on acetic acid(AA) -induced UC in rats, with particular emphasis on its anti-inflammatory effects and its influence on NFκB/TNF-α/RIPK1 necroptotic pathways.

METHODS

Eighteen rats were allocated into control, acetic acid-induced colitis (AA), and DHA-treated (AA+DHA) groups. Colitis was caused by rectal instillation of 5 % acetic acid. DHA was supplied via intraperitoneal injection. Histological, biochemical studies of oxidative stress, inflammatory and anti-inflammatory mediators, Western blotting for TNF-α, RIPK1, and caspase 3, and immunohistochemical assessment of NFκB, TNF-α, and RIPK1, were conducted.

RESULTS

DHA treatment markedly diminished macroscopic damage, disease activity index, histopathology scores, and malondialdehyde (MDA) levels, enhancing glutathione (GSH) levels. Additionally, DHA decreased serum TNF-α and IL-6 and increased IL-10. Western blotting and immunohistochemistry investigations validated the reduced expression of TNF-α, RIPK1, and caspase 3 in DHA-treated rats.

CONCLUSION

DHA demonstrates protective properties against acetic acid-induced UC by decreasing oxidative stress and inflammation, modifying TNF-α activity to regulate apoptotic and necroptotic pathways. So, DHA may be a favorable therapeutic alternative for the management of ulcerative colitis.

Live and let die: analyzing ultrastructural features in cell death

Cell death is an important process that supports morphogenesis during development and tissue homeostasis during adult life by removing damaged or unwanted cells and its dysregulation is associated with numerous disease states. There are different pathways through which a cell can undergo cell death, each relying on peculiar molecular mechanisms and morpho-ultrastructural features. To date, however, while molecular and genetic approaches have been successfully integrated into the field, cell death studies rarely incorporate ultrastructural data from electron microscopy. This review article reports a gallery of original transmission electron microscopy images to describe the ultrastructural features of cells undergoing different types of cell death programs, including necrosis, apoptosis, autophagy, mitotic catastrophe, ferroptosis, methuosis, and paraptosis. TEM has been an important technology in cell biology for well over 50 years and still continues to offer significant advantages in the area of cell death research. TEM allows detailed characterization of the ultrastructural changes within the cell, such as the alteration of organelles and subcellular structures, the nuclear reorganization, and the loss of membrane integrity that enable a distinction between the different forms of cell death based on morphological criteria. Possible pitfalls are also described.

Short-term exposure to low doses of aflatoxin B1 aggravates nonalcoholic steatohepatitis by TLR4-mediated necroptosis

Aflatoxin B1 (AFB1), a worldwide mycotoxin found in food and foodstuffs, is a potent hepatotoxin in humans and animals. Non-alcoholic fatty liver disease (NAFLD), a widespread disease, could progress from simple steatosis to non-alcoholic steatohepatitis (NASH), hepatic cirrhosis, and even hepatocellular carcinoma (HCC). To date, little is known concerning the relationship between AFB1 and the progression of NAFLD. The effects of low doses of AFB1 on the development of NASH and their mechanism were investigated in vivo and in vitro. The results in vivo showed that AFB1 at 20 and 40 μg/kg.bw aggravated CDAHFD-induced NASH in mice as demonstrated by increasing the serum and liver lipid accumulation, liver inflammation and injury. The results in vitro showed that AFB1 at 1.0 μM aggravated FFA-induced lipid accumulation, inflammation and cell damage in HepG2 cells. In addition, RNA-seq indicated that necroptosis, Toll like receptor signaling and TNF-α signaling showed a significant change in KEGG pathway enrichment in AFB1 at 40 μg/kg.bw. AFB1 significantly upregulated the mRNA and protein levels of TLR4, RIPK3, p-RIPK3, MLKL and p-MLKL, and increased TUNEL positive cells. Also, immunofluorescence results showed that TUNEL, TLR4, TNF-α had co-localized with RIPK3, respectively. Necroptosis inhibitor (GSK-872) attenuated the aggravating effects of AFB1 on NASH. Knockout of TLR4 inhibited necroptosis and rescued the aggravating effects of AFB1 on NASH. These data indicate that low dose of AFB1 aggravated NASH via TLR4-mediated necroptosis. This suggests that low dose of AFB1 is potentially harmful to animals and humans, as they exacerbate NASH.

Intestinal pathology in goats challenged with Clostridium perfringens type D strain CN1020 wild-type and its genetically modified derivatives

Clostridium perfringens type D is the causative agent of enterotoxemia in sheep, goats, and cattle. Although in sheep and cattle, the disease is mainly characterized by neurological clinical signs and lesions, goats with type D enterotoxemia frequently have alterations of the alimentary system. Epsilon toxin (ETX) is the main virulence factor of C. perfringens type D, although the role of ETX in intestinal lesions in goats with type D enterotoxemia has not been fully characterized. We evaluated the contribution of ETX to C. perfringens type D enteric pathogenicity using an intraduodenal challenge model in young goats, with the virulent C. perfringens type D wild-type strain CN1020; its isogenic etx null mutant; an etx-complemented strain; and sterile, non-toxic culture medium. The intestinal tract of each animal was evaluated grossly, microscopically, and immunohistochemically for activated caspase-3. Both ETX-producing strains induced extensive enterocolitis characterized by severe mucosal necrosis, apoptosis, and diffuse suppurative infiltrates. No significant gross or microscopic lesions were observed in goats inoculated with the non-ETX-containing inocula. These results confirm that ETX is essential for the production of intestinal lesions in goats with type D disease. Also, our results suggest that the intestinal pathology of type D enterotoxemia in goats is, at least in part, associated with apoptosis.

Harnessing luciferase chemistry in regulated cell death modalities and autophagy: overview and perspectives

Regulated cell death is a fate of cells in (patho)physiological conditions during which extrinsic or intrinsic signals or redox equilibrium pathways following infection, cellular stress or injury are coupled to cell death modalities like apoptosis, necroptosis, pyroptosis or ferroptosis. An immediate survival response to cellular stress is often induction of autophagy, a process that deals with removal of aggregated proteins and damaged organelles by a lysosomal recycling process. These cellular processes and their regulation are crucial in several human diseases. Exploiting high-throughput assays which discriminate distinct cell death modalities and autophagy are critical to identify potential therapeutic agents that modulate these cellular responses. In the past few years, luciferase-based assays have been widely developed for assessing regulated cell death and autophagy pathways due to their simplicity, sensitivity, known chemistry, different spectral properties and high-throughput potential. Here, we review basic principles of bioluminescent reactions from a mechanistic perspective, along with their implication in vitro and in vivo for probing cell death and autophagy pathways. These include applying luciferase-, luciferin-, and ATP-based biosensors for investigating regulated cell death modalities. We discuss multiplex bioluminescence platforms which simultaneously distinguish between the various cell death phenomena and cellular stress recovery processes such as autophagy. We also highlight the recent technological achievements of bioluminescent tools for the prediction of drug effectiveness in pathways associated with regulated cell death.

Effects of Hermetia illucens larvae meal and astaxanthin on intestinal histology and expression of tight junction proteins in weaned piglets

The weaning phase in piglets causes significant physiological stress, disrupts intestinal integrity and reduces productivity, necessitating strategies to improve intestinal health and nutrient absorption. While current research highlights the role of diet in mitigating these adverse effects, identifying effective dietary supplements remains a challenge. This study evaluated the effects of Hermetia illucens (HI) larvae meal and astaxanthin (AST) on the intestinal histology of weaned piglets. In a controlled experiment, 48 weaned piglets were divided into six groups and received varying levels of HI larval meal (2.5% and 5%) and AST in their diets. The methodology involved comprehensive histological examinations of the small intestine, assessing absorption area, villi elongation, crypt depth, goblet cells, enterocytes and expression of ileal tight junction (TJ) proteins. The study found that HI larval meal significantly improved nutrient absorption in the jejunum and ileum (p < 0.001), thereby enhancing feed conversion. AST supplementation increased the number of enterocytes (p < 0.001). Both HI larval meal and AST positively affected intestinal morphology and function, increasing muscularis muscle mass and villi elongation (p < 0.001 and p < 0.05, respectively). The 2.5% HI meal improved the villi length to crypt depth ratio and slightly increased the goblet cell count (both p < 0.05). Ki-67 antibody analysis showed increased cell proliferation in the duodenal and jejunal crypts, particularly with the 2.5% HI meal (p < 0.001). Insect meal did not affect TJ protein expression, indicating that it had no effect on intestinal permeability. These findings suggest that HI larval meal and AST can enhance the intestinal wellness and productivity of weaned piglets.

Apoptotic and proliferative processes in the small intestine of rats with type 2 diabetes mellitus after metformin and propionic acid treatment

Background

Propionic acid (PA) is an intermediate product of metabolism of intestinal bacteria and may protect the intestinal barrier from disruption. The aim of the study was to investigate the apoptotic and proliferative processes in the small intestine (SI) of rats with type 2 diabetes mellitus (T2DM) on the background of metformin monotherapy and its combination with PA.

Methods

Male Wistar rats were divided: 1) control; 2) T2DM (3-month high-fat diet followed by streptozotocin injection of 25 mg/kg of body weight); 3) T2DM + metformin (60 mg/kg, 14 days, orally); 4) T2DM + PA (60 mg/kg, 14 days, orally); 5) T2DM + PA + metformin. Western blotting, RT-PCR, and scanning electron microscopy were performed.

Results

We observed profound changes in the SI of diabetic rats suggesting the disturbed intestinal homeostasis: impaired mitochondrial ultrastructure, increased cristae volume, and decreased content of proliferative marker Ki67 with almost unchanged proapoptotic caspase-3 and its p17 subunit levels. Metformin and PA monotherapies also led to an increased cristae volume, however, after their combination, a tendency to normalization of ultrastructure of mitochondria was observed. While there was a significant inhibition of proliferation in T2DM and, in greater extent, after metformin and PA monotherapies, differential influence on apoptosis in the SI was observed. While metformin inhibited apoptosis via Bax declining, PA mainly acted via caspase-3-dependent mechanism elevating its active p17 subunit.

Conclusion

PA supplementation for the improvement of diabetes-induced gastrointestinal complications concurrently with metformin may be consider as a perspective supportive therapy. Data related to PA action on SI may be valuable during the development of new treatment strategies for diabetes-induced intestinal disturbances raised after metformin treatment.

The impacts of microplastics on zebrafish behavior depend on initial personality state

Microplastic pollution is associated with inflammation, gut dysbiosis and behavioral changes in fish. Fish have distinct personality traits but the role of personality in behavioral toxicology is rarely considered. We classified zebrafish on four behavioral axes: boldness, anxiety, sociability and exploration tendency then exposed them to low- or high- concentrations of two types of polyethylene microplastics (low- and high-density) for 28 days. Behaviors, antioxidant enzymes (catalase and superoxide dismutase), and gut microbiome were then measured. There were direct effects of microplastics on boldness, anxiety and sociability. However, fish retained their initial behavioral tendencies. Exposure to all microplastic treatments reduced average swimming speed and decreased the time spent motionless. Microplastic exposure did not affect antioxidant enzymes but did cause significant changes in the composition of the gut microbiome. This study demonstrates that environmentally realistic concentrations of microplastics can alter fish behavior, but much of the variance in response can be explained by personality.

RIP3 regulates doxorubicin-induced intestinal mucositis via FUT2-mediated α-1,2-fucosylation

OBJECTIVE

Intestinal mucositis is one of the common side effects of anti-cancer chemotherapy. However, the molecular mechanisms involved in mucositis development remain incompletely understood. In this study, we investigated the function of receptor-interacting protein kinase 3 (RIP3/RIPK3) in regulating doxorubicin-induced intestinal mucositis and its potential mechanisms.

METHODS

Intestinal mucositis animal models were induced in mice for in vivo studies. Rat intestinal cell line IEC-6 was used for in vitro studies. RNA‑seq was used to explore the transcriptomic changes in doxorubicin-induced intestinal mucositis. Intact glycopeptide characterization using mass spectrometry was applied to identify α-1,2-fucosylated proteins associated with mucositis.

RESULTS

Doxorubicin treatment increased RIP3 expression in the intestine and caused severe intestinal mucositis in the mice, depletion of RIP3 abolished doxorubicin-induced intestinal mucositis. RIP3-mediated doxorubicin-induced mucositis did not depend on mixed lineage kinase domain-like (MLKL) but on α-1,2-fucosyltransferase 2 (FUT2)-catalyzed α-1,2-fucosylation on inflammation-related proteins. Deficiency of MLKL did not affect intestinal mucositis, whereas inhibition of α-1,2-fucosylation by 2-deoxy-D-galactose (2dGal) profoundly attenuated doxorubicin-induced inflammation and mucositis.

CONCLUSIONS

RIP3-FUT2 pathway is a central node in doxorubicin-induced intestinal mucositis. Targeting intestinal RIP3 and/or FUT2-mediated α-1,2-fucosylation may provide potential targets for preventing chemotherapy-induced intestinal mucositis.

Significance of Necroptosis in Cartilage Degeneration

Cartilage, a critical tissue for joint function, often degenerates due to osteoarthritis (OA), rheumatoid arthritis (RA), and trauma. Recent research underscores necroptosis, a regulated form of necrosis, as a key player in cartilage degradation. Unlike apoptosis, necroptosis triggers robust inflammatory responses, exacerbating tissue damage. Key mediators such as receptor-interacting serine/threonine-protein kinase-1 (RIPK1), receptor-interacting serine/threonine-protein kinase-3(RIPK3), and mixed lineage kinase domain-like (MLKL) are pivotal in this process. Studies reveal necroptosis contributes significantly to OA and RA pathophysiology, where elevated RIPK3 and associated proteins drive cartilage degradation. Targeting necroptotic pathways shows promise; inhibitors like Necrostatin-1 (Nec-1), GSK'872, and Necrosulfonamide (NSA) reduce necroptotic cell death, offering potential therapeutic avenues. Additionally, autophagy's role in mitigating necroptosis-induced damage highlights the need for comprehensive strategies addressing multiple pathways. Despite these insights, further research is essential to fully understand necroptosis' mechanisms and develop effective treatments. This review synthesizes current knowledge on necroptosis in cartilage degeneration, aiming to inform novel therapeutic approaches for OA, RA, and trauma.

Lauric acid reduces apoptosis by inhibiting FOXO3a-signaling in deoxynivalenol-treated IPEC-J2 cells

Deoxynivalenol (DON) is the most common mycotoxin contaminant of food or feed worldwide and causes disease in animals. Lauric acid (LA) is a medium-chain fatty acid useful for barrier functions such as antimicrobial activity in the intestine of monogastric animals. However, the molecular mechanisms by which lauric acid exerts its effects on the deoxynivalenol-exposed small intestine have not been studied. We used an intestinal porcine epithelial cell line (IPEC-J2) as an in vitro model to explore the molecular mechanism of lauric acid in alleviating deoxynivalenol-induced damage. We found that lauric acid reversed deoxynivalenol-induced reduction in cell viability. Our quantitative real-time polymerase chain reaction results indicated that lauric acid alleviated deoxynivalenol-induced apoptosis through Annexin-V. Additionally, immunofluorescence and Western blotting showed that lauric acid attenuated deoxynivalenol-induced forkhead box O3 (FOXO3a) translocation into the nucleus. These results suggest that lauric acid attenuates forkhead box O3 translocation in the small intestine damaged by deoxynivalenol, thereby reducing apoptosis. In conclusion, this study found that lauric acid alleviates deoxynivalenol-induced damage in intestinal porcine epithelial cell line through various molecular mechanisms.

Linderae Radix extract attenuates ulcerative colitis by inhibiting the JAK/STAT signaling pathway

BACKGROUND

Linderae Radix (LR), the dried root of Lindera aggregata (Sims) Kosterm., is a traditional Chinese herbal medicine that has been used for thousands of years for promoting Qi circulation, soothing the liver, and treating diarrhea and dysentery. Previous studies have found that ethanol extract of LR plays an anti-ulcerative colitis (UC) role by regulating Th17/ Treg balance. Water extract is the classic clinical application form of LR, but the effect of water extract of LR (LRWE) on UC and its underlying mechanism is still unclear.

PURPOSE

Purpose: UC is a gastrointestinal disease characterized by intestinal inflammation, mucosal injury, and fibrosis, and it is one of the high-risk factors for colon cancer. However, there is still a lack of remedies with satisfactory effects. This study aimed to investigate the efficacy and the potential mechanism of LRWE against UC.

METHODS

LRWE samples were prepared using a reflux extraction method. Colitis in mice was induced by administering 2.5 % DSS water solution to evaluate the therapeutic effect of LRWE by assessing disease activity score, colon length, and fecal morphology. H&E staining, TEM, Masson staining, and AB-PAS staining were applied to observe histopathological changes in the colon tissues. Differentially expressed genes in colon tissues were analyzed by transcriptomics. Cell apoptosis was detected by TUNEL staining. The expression of inflammatory factors such as IL-6 and IL-1β, as well as the expression of p-STAT1, p-JAK2, p-STAT3, Bax, and Bcl-2, were detected by immunofluorescence and immunohistochemistry. The expression of occludin, Bcl-2, Bax, and JAK/STAT signaling pathway-related vital proteins were quantified by Western blot (WB).

RESULTS

LRWE alleviated body weight loss, colon shortening, DAI scores, pathological changes, and ultrastructural features of colon tissue in mice with colitis. It also inhibited the increase of pro-inflammatory cytokines (such as TNF-α, IL-6, and IL-1β) and increased IL-10 levels. Additionally, it protected the intestinal barrier by upregulating the expression of Occludin and Mucin-2. Mechanistically, LRWE could inhibit the activation of JAK-STAT signaling pathway by reducing the protein expression of p-JAK2, p-STAT3, p-STAT1, Bcl2, and Bax, thus reducing the inflammatory responses and inhibiting cell apoptosis.

CONCLUSION

LRWE has a protective effect on DSS-induced UC. This effect is related to the inhibition of the JAK-STAT signaling pathway, the improvement of intestinal inflammation, and the reduction of intestinal epithelial cell apoptosis.

Efficacy of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of young pigs

This study aimed to determine the effects of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of pigs. Thirty-two newly weaned pigs at 6.05 ± 0.24 kg were assigned to two dietary treatments based on a randomized complete block design. The treatments were control group receiving a basal diet and a group supplemented with Saccharomyces yeast postbiotics (175 g/ton diet) in the basal diet. After 35 d of the study, pigs were euthanized and jejunal mucosa were collected to assess immune status, oxidative stress, barrier markers, cell proliferation, and apoptosis. Saccharomyces yeast postbiotics reduced (P < 0.05) the fecal score from d 3 to d 7 and tended to increase the gene expression of interferon-γ (IFN-γ) (P = 0.071) and mammalian/mechanistic target of rapamycin (mTOR) (P = 0.080), decrease the gene expression of B-cell lymphoma 2-associated X protein 1 (BAX1) (P < 0.05), tended to decrease the gene expression of serum and glucocorticoid-induced protein kinase 1 (SGK1) (P = 0.066), increased (P < 0.05) cell proliferation in the crypts, and tended to increase the villus height (P = 0.078) and crypt depth (P = 0.052) in the jejunum. In conclusion, the supplementation of Saccharomyces yeast postbiotics in nursery diets reduced diarrhea within the first week after weaning and provided protection to the villi in the jejunum by enhancing the immune responses of nursery pigs, promoting crypt cell proliferation, and reducing the expression of genes associated with apoptosis without affecting inflammatory and oxidative stress status in the jejunum of the nursery pigs.

Selenium attenuated food borne cadmium-induced intestinal inflammation in red swamp crayfish (Procambarus clarkii) via regulating PI3K/Akt/NF-κB pathway

Selenium (Se), an indispensable micronutrient for living organisms, has been extensively studied for its heavy metal-detoxifying properties in diverse biological systems and tissues. Nevertheless, it is not entirely certain whether Se can effectively protect against Cadmium (Cd)-induced gut inflammation, especially in aquatic animals. In this study, we employed various approaches, including transcriptome profiling, histological examinations, assessment of antioxidant enzyme activities, and analysis of gut microbiota composition to investigate the effects on crayfish growth and intestinal health after exposure to dietary Cd (15 mg kg-1 diet) and Se (15 mg kg-1 diet) individually or in combination for 8 weeks. The results revealed that dietary Cd exposure resulted in reduced body weight and survival rates, along with an increased occurrence of intestinal inflammation. Nevertheless, Se supplementation proved effective in mitigating the adverse effects of Cd on growth and gut health. Se exhibited a remarkable ability to counteract the disruption of gut antioxidant abilities induced by dietary Cd, as evidenced by the observed increases in ROS and MDA contents, decrease in GSH levels, and inhibition of antioxidative enzyme activities. At the concentration of 6 mg kg-1 in the diet, Se was found beneficial for maintaining gut microbiota richness and diversity. Among them, Flavobacterium, Thermomonas, and Chloronema displayed a weak negative correlation with the rate of gut inflammation. Meanwhile, the levels of short chain fatty acids (SCFAs), including acetic acid (AA) and butanoic acid (BA), showed a significant increase in the Se-Cd group compared to the Cd-only group. Furthermore, transcriptome analysis exhibited significant responses of the PI3K/Akt and NF-κB pathways following crayfish exposure to dietary Se and Cd, either separately or in combination. In short, this study provides a new evidence regarding the molecular mechanisms through which Se could regulate the PI3K/Akt and NF-κB pathways, either directly or indirectly via ROS and SCFAs, thereby alleviating Cd-induced gut inflammation in crayfish.

Intraepithelial lymphocytes are associated with epithelial injury in feline intestinal T-cell lymphoma

Our previous study indicated that cytotoxicity of intraepithelial lymphocytes is a poor prognostic factor in feline intestinal T-cell lymphoma (FITL), but the effect of cytotoxic lymphocytes on mucosal epithelium is still unknown. Thus, we investigated the association between cytotoxic lymphocytes and mucosal epithelium in 71 cases of feline intestinal T-cell lymphoma (FITL): epithelial injury, basement membrane injury, cleaved-caspase-3 positivity of epithelial cells, and the number and Ki67 positivity of intraepithelial lymphocytes in granzyme B (GRB)+ and GRB- FITLs were evaluated. Epithelial injury score and the number of intraepithelial lymphocytes in granzyme B (GRB)+ FITL were significantly higher than those of GRB- FITL (P<0.05, P<0.05), but no significant differences were found in the basement membrane injury score, the percentage of cleaved-caspase-3+ epithelial cells, and the percentage of Ki67+ intraepithelial lymphocytes. There was a significant correlation between the epithelial injury score and the number of intraepithelial lymphocytes (P<0.05), but no significant correlation was observed between the epithelial injury score and Ki67+ percentage of intraepithelial lymphocytes. Because epithelial cell cleaved-caspase-3 positivity was observed in FITL, regardless of GRB expression in lymphocytes, GRB-mediated apoptosis may not contribute to epithelial injury in FITL. The association between increased number of intraepithelial lymphocytes and epithelial injury suggests that intraepithelial lymphocytes infiltration may contribute to epithelial injury in FITL.

Human gut homeostasis and regeneration: the role of the gut microbiota and its metabolites

The healthy human gut is a balanced ecosystem where host cells and representatives of the gut microbiota interact and communicate in a bidirectional manner at the gut epithelium. As a result of these interactions, many local and systemic processes necessary for host functionality, and ultimately health, take place. Impairment of the integrity of the gut epithelium diminishes its ability to act as an effective gut barrier, can contribute to conditions associated to inflammation processes and can have other negative consequences. Pathogens and pathobionts have been linked with damage of the integrity of the gut epithelium, but other components of the gut microbiota and some of their metabolites can contribute to its repair and regeneration. Here, we review what is known about the effect of bacterial metabolites on the gut epithelium and, more specifically, on the regulation of repair by intestinal stem cells and the regulation of the immune system in the gut. Additionally, we explore the potential therapeutic use of targeted modulation of the gut microbiota to maintain and improve gut homeostasis as a mean to improve health outcomes.

Role of Necroptosis in Intervertebral Disc Degeneration

Apoptosis has historically been considered the primary form of programmed cell death (PCD) and is responsible for regulating cellular processes during development, homeostasis, and disease. Conversely, necrosis was considered uncontrolled and unregulated. However, recent evidence has unveiled the significance of necroptosis, a regulated form of necrosis, as an important mechanism of PCD alongside apoptosis. The activation of necroptosis leads to cellular membrane disruption, inflammation, and vascularization. This process is crucial in various pathological conditions, including intervertebral disc degeneration (IVDD), neurodegeneration, inflammatory diseases, multiple cancers, and kidney injury. In recent years, extensive research efforts have shed light on the molecular regulation of the necroptotic pathway. Various stimuli trigger necroptosis, and its regulation involves the activation of specific proteins such as receptor-interacting protein kinase 1 (RIPK1), RIPK3, and the mixed lineage kinase domain-like (MLKL) pseudokinase. Understanding the intricate mechanisms governing necroptosis holds great promise for developing novel therapeutic interventions targeting necroptosis-associated IVDD. The objective of this review is to contribute to the growing body of scientific knowledge in this area by providing a comprehensive overview of necroptosis and its association with IVDD. Ultimately, these understandings will allow the development of innovative drugs that can modulate the necroptotic pathway, offering new therapeutic avenues for individuals suffering from necroptosis.

Seeing beyond apoptosis: ultrastructural aspects of necrosis in human atherosclerosis

In recent years, there has been an explosive growth of research to decipher the pathobiologic relevance of cell death in the development and progression of various cardiovascular disorders such as arterial remodeling and atherosclerosis. High rates of cell death have been reported in animal models, particularly following balloon catheter injury. Also, in humans there is considerable evidence indicating a close connection between cell death and atherosclerosis. In this regard, diverse biochemical and molecular analysis have suggested that intraplaque cells preferentially die by apoptosis, a mode of cell death considered to be active, highly regulated and programmed. In contrast to apoptosis, necrosis has been classically defined as an uncontrolled form of cell death that can occur in response to chemical or physical insults such as trauma, infection, toxins, or lack of blood supply. Necrosis has long been known to be present within atherosclerotic plaques but to date it is still less well understood and characterized than apoptosis. In addition, although electron microscopy (EM) remains essential in cell death research, only a very small proportion of studies deal with the ultrastructural aspects of cell death and/or include EM images to support their findings. As a consequence, many features of cell death modes in human atherosclerosis have not yet been thoroughly investigated and defined. The present study was undertaken to provide an ultrastructural description of the route/s by which intraplaque cells can die also suggesting novel insights for future research.

Prediction models combining zonulin, LPS, and LBP predict acute kidney injury and hepatorenal syndrome-acute kidney injury in cirrhotic patients

The development of acute kidney injury (AKI) and hepatorenal syndrome-acute kidney injury (HRS-AKI) in cirrhosis has been associated with intestinal barrier dysfunction and gut-kidney crosstalk. We use the related markers such as zonulin, lipopolysaccharides (LPS), and lipopolysaccharide-binding protein (LBP) to predict AKI and HRS-AKI in cirrhotic patients and evaluate their in vitro effects on intestinal (Caco-2) cells and renal tubular (HK-2) cells. From 2013 to 2020, we enrolled 70 cirrhotic patients and developed prediction models for AKI and HRS-AKI over a six-month period. There were 13 (18.6%) and 8 (11.4%) cirrhotic patients developed AKI and HRS-AKI. The prediction models incorporated zonulin, LPS, LBP, C-reactive protein, age, and history of hepatitis B for AKI, and zonulin, LPS, LBP, total bilirubin, and Child-Pugh score for HRS-AKI. The area under curve (AUC) for the prediction of AKI and HRS-AKI was 0.94 and 0.95, respectively. Furthermore, the conditioned medium of LPS+hrLBP pre-treated Caco-2 cells induced apoptosis, necrosis, and zonulin release in HK-2 cells, demonstrating the communication between them. This study found that zonulin, LPS, and LBP are potential practical markers for predicting AKI and HRS-AKI in cirrhotic patients, which may serve as potential targets for renal outcomes in cirrhotic patients.

Direct and indirect effects of alcohol and its toxic metabolite acetaldehyde on human esophageal myofibroblasts and epithelial cells

BACKGROUND

Mechanisms by which alcohol increases the risk of esophageal squamous cell carcinoma remain undefined. Human esophageal myofibroblasts (HEMFs) subjacent to the squamous epithelium are exposed directly to these agents via epithelial barrier defects and indirectly via factors derived from the exposed epithelium. Our aim was to investigate the cellular biology of HEMFs and HEMF-esophageal epithelial cell interactions in response to alcohol and its toxic metabolite acetaldehyde.

METHODS

An immortalized HEMF and a human esophageal epithelial cell line (Epi) were treated with alcohol (0 to 200 mM) or acetaldehyde (0 to 100 μM) in a cyclic fashion or incubated with supernatants collected from treated cells. Healthy cell %, reactive oxygen species (ROS), and proliferation were assessed via flow cytometry, luminescence, scratch wound, and colorimetric assays, respectively. A 15-plex multiplex assay was performed on cell supernatants, followed by IL-6 and IL-8 qRT-PCR and ELISA.

RESULTS

Healthy HEMF decreased to less than 80% at 30 mM alcohol and 70 μM acetaldehyde, with microscopic changes at 40 μM acetaldehyde. HEMF ROS was detected at 100 mM alcohol and 80 μM acetaldehyde. Supernatants from 30 mM alcohol- or 40 μM acetaldehyde-treated HEMFs increased Epi proliferation more than two-fold that of lower doses. In the complementary studies, healthy Epi cells decreased to less than 80% at 50 mM and 70 μM acetaldehyde, with microscopic changes at 40 μM. Supernatants from Epi treated with 50 mM alcohol or 40 μM acetaldehyde increased HEMF proliferation more than two-fold that of lower doses. A multiplex assay of supernatants showed the greatest increase in concentrations of IL-6 and IL-8 in HEMFs and in Epi treated with higher doses of alcohol or acetaldehyde. Neutralization of IL-6 and IL-8 in supernatants of HEMFS and esophageal epithelial cells inhibited the proliferation of Epi and HEMFs, respectively.

CONCLUSIONS

Alcohol and acetaldehyde doses in which the majority of HEMFs and epithelial cells are healthy, elicit the production of paracrine mediators with pro-proliferative effects on neighboring cells. Understanding the effect of alcohol and acetaldehyde on HEMFs and HEMF-epithelial interactions could help to identify the molecular basis by which alcohol increases the risk for esophageal cancer.

Depletion of reactive oxygen species induced by beetroot (Beta vulgaris) extract leads to apoptosis-like death in Cronobacter sakazakii

This research aimed to disclose the antibacterial activity of beetroot extract (Beta vulgaris) against Cronobacter sakazakii and its possible mechanisms. We evaluated its antibacterial activity by measuring the minimum inhibitory concentration (MIC) and time-kill kinetics. We also evaluated the intracellular ATP levels, bacterial apoptosis-like death (ALD), and reactive oxygen species (ROS) levels to reveal the possible antibacterial mechanisms. Our results showed that the MIC of beetroot extract against C. sakazakii was 25 mg/mL and C. sakazakii (approximately 8 log cfu/mL) was completely inhibited after treatment with 2 MIC of beetroot extract for 3 h. Beetroot extract reduced intracellular ATP levels and facilitated characteristics of ALD in C. sakazakii, such as membrane depolarization, increased intracellular Ca²⁺ levels, phosphatidylserine externalization, caspase-like protein activation, and DNA fragmentation. Additionally, and different from most bacterial ALD caused by the accumulation of ROS, beetroot extract reduced the intracellular ROS levels in C. sakazakii. Our experimental data provide a rationale for further research of bacterial ALD and demonstrate that beetroot extract can inhibit C. sakazakii in food processing environments.

Melatonin and 5-fluorouracil combination chemotherapy: opportunities and efficacy in cancer therapy

Combined chemotherapy is a treatment method based on the simultaneous use of two or more therapeutic agents; it is frequently necessary to produce a more effective treatment for cancer patients. Such combined treatments often improve the outcomes over that of the monotherapy approach, as the drugs synergistically target critical cell signaling pathways or work independently at different oncostatic sites. A better prognosis has been reported in patients treated with combination therapy than in patients treated with single drug chemotherapy. In recent decades, 5-fluorouracil (5-FU) has become one of the most widely used chemotherapy agents in cancer treatment. This medication, which is soluble in water, is used as the first line of anti-neoplastic agent in the treatment of several cancer types including breast, head and neck, stomach and colon cancer. Within the last three decades, many studies have investigated melatonin as an anti-cancer agent; this molecule exhibits various functions in controlling the behavior of cancer cells, such as inhibiting cell growth, inducing apoptosis, and inhibiting invasion. The aim of this review is to comprehensively evaluate the role of melatonin as a complementary agent with 5-FU-based chemotherapy for cancers. Additionally, we identify the potential common signaling pathways by which melatonin and 5-FU interact to enhance the efficacy of the combined therapy. Video abstract.

UVA induces retinal photoreceptor cell death via receptor interacting protein 3 kinase mediated necroptosis

Ultraviolet light A (UVA) is the only UV light that reaches the retina and can cause indirect damage to DNA via absorption of photons by non-DNA chromophores. Previous studies demonstrate that UVA generates reactive oxygen species (ROS) and leads to programmed cell death. Programmed cell death (PCD) has been implicated in numerous ophthalmologic diseases. Here, we investigated receptor interacting protein 1 and 3 (RIPK1 and RIPK3) kinases, key signaling molecules of PCD, in UVA-induced photoreceptor injury using in vitro and ex vivo models. UVA irradiation activated RIPK3 but not RIPK1 and mediated necroptosis through MLKL that lie downstream of RIPK3 and induced apoptosis through increased oxidative stress. Moreover, RIPK3 but not RIPK1 inhibition suppresses UVA-induced cell death along with the downregulation of MLKL and attenuates the levels of oxidative stress and DNA fragmentation. In conclusion, these results identify RIPK3, not RIPK1, as a critical regulator of UVA-induced necroptosis cell death in photoreceptors and highlight RIPK3 potential as a neuroprotective target.

Oxidative Stress-Induced HMGB1 Translocation in Myenteric Neurons Contributes to Neuropathy in Colitis

High-mobility group box 1 (HMGB1) is a damage-associated molecular pattern released by dying cells to stimulate the immune response. During cell death, HMGB1 is translocated from the nucleus to the cytoplasm and passively released. High levels of secreted HMGB1 are observed in the faeces of inflammatory bowel disease (IBD) patients, indicating its role in IBD pathophysiology and potential as a non-invasive IBD biomarker. HMGB1 is important in regulating neuronal damage in the central nervous system; its pathological activity is intertwined with oxidative stress and inflammation. In this study, HMGB1 expression in the enteric nervous system and its relevance to intestinal neuroinflammation is explored in organotypic cultures of the myenteric plexus exposed to oxidative stimuli and in Winnie mice with spontaneous chronic colitis. Oxidative stimuli induced cytoplasmic translocation of HMGB1 in myenteric neurons in organotypic preparations. HMGB1 translocation correlated with enteric neuronal loss and oxidative stress in the myenteric ganglia of Winnie mice. Inhibition of HMGB1 by glycyrrhizic acid ameliorated HMGB1 translocation and myenteric neuronal loss in Winnie mice. These data highlight modulation of HMGB1 signalling as a therapeutic strategy to reduce the consequences of enteric neuroinflammation in colitis, warranting the exploration of therapeutics acting on the HMGB1 pathway as an adjunct treatment with current anti-inflammatory agents.

Prevention of ulcerative colitis by Huangqin decoction: reducing the intestinal epithelial cell apoptosis rate through the IFN-γ/JAK/ETS signalling pathway

CONTEXT

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disease that is closely related to inflammation and apoptosis. The traditional Chinese medicine compound preparation Huangqin decoction (HQD) has been widely used in the clinical treatment of UC, but the specific mechanism of its function is still inconclusive.

OBJECTIVE

To explore the pathogenesis of UC based on the IFN-γ/JAK/ETS signalling pathway, and to clarify the biological mechanism of HQD.

MATERIALS AND METHODS

Forty 8-week-old male C57BL/6 mice were randomly divided into four groups: normal control, model, model + salazosulfapyridine group (500 mg/kg, p.o., pd) and model + HQD (9.1 g/kg, p.o., pd). Using Dextran sulphate sodium (DSS) salt (2.5%, p.o.)+high-fat diet + hot and humid environment to build a mouse model of UC. One month later, the changes of colon morphology, serum inflammatory factors, intestinal epithelial cell apoptosis and IFN-γ/JAK/ETS signalling pathway related protein changes in mice were observed.

RESULTS

Compared with the model group, HQD significantly reduced the pathological score of the model mice's colon (2.60 ± 0.25 vs. 4.80 ± 0.37), and reduced the serum IFN-γ (200.30 ± 8.45 vs. 413.80 ± 6.97) and other inflammatory factors, and reduced intestinal epithelial cell apoptosis (24.85 ± 4.87 vs. 214.90 ± 39.21). In terms of mechanism, HQD down-regulated IFN-γ/JAK/ETS signalling pathway related proteins in colon tissue of UC model mice.

CONCLUSIONS

These data indicate that HQD can improve UC by reducing intestinal inflammation and apoptosis, providing experimental evidence for the wide application of HQD in clinical practice of UC.

P2X7 Receptor and Purinergic Signaling: Orchestrating Mitochondrial Dysfunction in Neurodegenerative Diseases

Mitochondrial dysfunction is one of the basic hallmarks of cellular pathology in neurodegenerative diseases. Since the metabolic activity of neurons is highly dependent on energy supply, nerve cells are especially vulnerable to impaired mitochondrial function. Besides providing oxidative phosphorylation, mitochondria are also involved in controlling levels of second messengers such as Ca2+ ions and reactive oxygen species (ROS). Interestingly, the critical role of mitochondria as producers of ROS is closely related to P2XR purinergic receptors, the activity of which is modulated by free radicals. Here, we review the relationships between the purinergic signaling system and affected mitochondrial function. Purinergic signaling regulates numerous vital biological processes in the CNS. The two main purines, ATP and adenosine, act as excitatory and inhibitory neurotransmitters, respectively. Current evidence suggests that purinergic signaling best explains how neuronal activity is related to neuronal electrical activity and energy homeostasis, especially in the development of Alzheimer's and Parkinson's diseases. In this review, we focus on the mechanisms underlying the involvement of the P2RX7 purinoreceptor in triggering mitochondrial dysfunction during the development of neurodegenerative disorders. We also summarize various avenues by which the purine signaling pathway may trigger metabolic dysfunction contributing to neuronal death and the inflammatory activation of glial cells. Finally, we discuss the potential role of the purinergic system in the search for new therapeutic approaches to treat neurodegenerative diseases.

Occurrences and phenotypes of RIPK3-positive gastric cells in Helicobacter pylori infected gastritis and atrophic lesions

BACKGROUND

Research evidences suggest that diverse forms of programmed cell death (PCD) are involved in the helicobacter pylori (H. pylori)-induced gastric inflammation and disorders.

AIMS

To characterize occurrences and phenotypes of necroptosis in gastric cells in H. pylori infected gastritis and atrophic specimens.

METHODS

Occurrences and phenotypes of necroptosis in gastric cells were immunohistochemically characterized with receptor-interacting protein kinase 3 (RIPK3) antibody in both human H. pylori infected gastric gastritis, atrophic specimens, and transgenic mice.

RESULTS

Increased populations of RIPK3-positive cells were observed in both gastric glands and lamina propria in H. pylori infected human oxyntic gastritis and atrophic specimens. Phenotypic analysis revealed that many RIPK3-positive cells were H ⁺ K⁺ ATPase-positive parietal cells in the gastric glands and were predominantly CD3-positive T lymphocytes, CD68-positive macrophages, and SMA-alpha-positive stromal cells in the lamina propria. Furthermore, we found an increased expression of RIPK3-positive gastric glandular cells along with the histological process of hyperplasia-atrophy-dysplasia progression in hypergastrinemic INS-GAS mice.

CONCLUSIONS

An increased population of RIPK3-positive cells was observed in several types of gastric cells, future studies that define the effects and mechanisms of PCD implicated in the development of H. pylori induced gastric disorders are needed.

Stand by me: Fibroblasts regulation of the intestinal epithelium during development and homeostasis

The epithelium of the small intestine is composed of a single layer of cells that line two functionally distinct compartments, the villi that project into the lumen of the gut and the crypts that descend into the underlying connective tissue. Stem cells are located in crypts, where they divide and give rise to transit-amplifying cells that differentiate into secretory and absorptive epithelial cells. Most differentiated cells travel upwards from the crypt towards the villus tip, where they shed into the lumen. While some of these cell behaviors are an intrinsic property of the epithelium, it is becoming evident that tight coordination between the epithelium and the underlying fibroblasts plays a critical role in tissue morphogenesis, stem-cell niche maintenance and regionalized gene expression along the crypt-villus axis. Here, we will review the current literature describing the interaction between epithelium and fibroblasts during crypt-villus axis development and intestinal epithelium renewal during homeostasis.

Cathelicidins Induce Toll-Interacting Protein Synthesis to Prevent Apoptosis in Colonic Epithelium

Cathelicidin peptides secreted by leukocytes and epithelial cells are microbicidal but also regulate pathogen sensing via toll-like receptors (TLRs) in the colon by mechanisms that are not fully understood. Herein, analyses with the attaching/effacing pathogen Citrobacter rodentium model of colitis in cathelicidin-deficient (Camp-/-) mice, and colonic epithelia demonstrate that cathelicidins prevent apoptosis by sustaining post-transcriptional synthesis of a TLR adapter, toll-interacting protein (TOLLIP). Cathelicidins induced phosphorylation-activation of epidermal growth factor receptor (EGFR)-kinase, which phosphorylated-inactivated miRNA-activating enzyme Argonaute 2 (AGO2), thus reducing availability of the TOLLIP repressor miRNA-31. Cathelicidins promoted stability of TOLLIP protein via a proteosome-dependent pathway. This cathelicidin-induced TOLLIP upregulation prevented apoptosis in the colonic epithelium by reducing levels of caspase-3 and poly (ADP-ribose) polymerase (PARP)-1 in response to the proinflammatory cytokines, interferon-γ (IFNγ) and tumor necrosis factor-α (TNFα). Further, Camp-/- colonic epithelial cells were more susceptible to apoptosis during C. rodentium infection than wild-type cells. This antiapoptotic effect of cathelicidins, maintaining epithelial TOLLIP protein in the gut, provides insight into cathelicidin's ability to regulate TLR signaling and prevent exacerbated inflammation.

Moringa oleifera alcoholic extract protected stomach from bisphenol A-induced gastric ulcer in rats via its anti-oxidant and anti-inflammatory activities

This study evaluated the protective potentials of Moringa oleifera leaf alcoholic extract (MOLE) against bisphenol A (BPA)-induced stomach ulceration and inflammation in rats. Control rats received olive oil. Second group administered MOLE (200 mg/kg bwt) by oral gavage. Third group was given BPA (50 mg/ kg bwt) for 4 weeks. Fourth group administrated BPA and MOLE simultaneously. Fifth group was given MOLE for 4 weeks then administered BPA and MOLE for another 4 weeks. Bisphenol A induced gastric ulceration and decreased the volume of gastric juice, prostaglandin E2 (PGE2), reduced glutathione (GSH) and interleukin 10 (IL-10) contents, superoxide dismutase (SOD) activity, and proliferating cell nuclear antigen (PCNA) protein in stomach tissues, while increased the titratable acidity, malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) contents, and caspase-3 and NF‑κB proteins in stomach tissue. However, MOLE ameliorated BPA-induced gastric ulceration and significantly increased the volume of gastric juice, PGE2, GSH and IL-10 contents, SOD activity, and PCNA protein while significantly decreased titratable acidity, MDA, TNF-α and IL-6 contents, and of NF‑κB and caspase-3 proteins in gastric tissue. This study indicated that MOLE protected stomach against BPA-induced gastric injury via its anti-oxidant, anti-apoptotic, and anti-inflammatory activities.

ABIN1 Inhibits Inflammation through Necroptosis-Dependent Pathway in Ulcerative Colitis

Background

Ulcerative colitis (UC) is characterized by chronic, recurrent intestinal inflammation and intestinal epithelial injury including a wide range of epithelial cell death, ulcers, crypt abscesses, and the formation of fibrosis. The intestinal barrier dysfunction runs through the whole process of the occurrence and development of UC. A recent study revealed that an ubiquitin binding protein ABIN1 played a role in tissue homeostasis and autoimmunity diseases which involved in the anti-inflammatory response of intestinal epithelia cells. However, the roles of ABIN1 in ulcerative colitis pathogenesis remain unclear.

Methods

The mRNA and protein expression level of ABIN1 and necroptosis-associated genes (RIPK1, RIPK3, and MLKL) were conducted to investigate the relationship between ABIN1 and necroptosis in clinical UC specimens. Subsequently, the dextran sodium sulfate (DSS)-induced mice colitis model was used to verify the ABIN1 function in vivo. Furthermore, we established ABIN1 gain and loss function assay in CACO-2 to confirm the mechanism in UC in vitro.

Results

We found that ABIN1, RIPK1, RIPK3, and MLKL were upregulated in UC sample and DSS-induced colitis. Upon TNF-α stimulation in the intestinal epithelia cell line, overexpression of ABIN1 significantly inhibits necroptosis in the intestinal inflammation model along with the reduction expression of pro-inflammatory cytokines such as IL1B, IL6, IL8, and TNF-α. Blocking RIPK1 by Nec-1s in vivo and in vitro dramatically alleviated the colitis and cell death which shares the same phenotype with ABIN1 overexpression.

Conclusion

Hence, the dysregulation of ABIN1 may relate to the uncontrolled necroptosis and inflammation in UC, and negatively regulate the occurrence and process of ulcerative colitis. ABIN1 activation may be considered a therapeutic strategy for UC.

Evaluation of Transcriptomic Responses in Livers of Mice Exposed to the Short-Chain PFAS Compound HFPO-DA

HFPO-DA (ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate; CASRN 62037-80-3) is a component of the GenX technology platform used as a polymerization aid in the manufacture of some types of fluoropolymers. The liver is the primary target of toxicity for HFPO-DA in rodents and previous examination of hepatic transcriptomic responses in mice following oral exposure to HFPO-DA for 90 days showed induction of peroxisome proliferator-activated receptor signaling pathways, predominantly by PPARα, as well as increased gene expression of both peroxisomal and mitochondrial fatty acid metabolism. To further investigate the mechanism of liver toxicity, transcriptomic analysis was conducted on liver tissue from mice orally exposed to 0, 0.1, 0.5 or 5 mg/kg-bw/day HFPO-DA in a reproduction/developmental toxicity study. Hepatic gene expression changes demonstrated activation of the PPARα signaling pathway. Peroxisomal and mitochondrial fatty acid β-oxidation gene sets were enriched at lower HFPO-DA concentrations, and complement cascade, cell cycle and apoptosis related gene sets were enriched at higher HFPO-DA concentrations. These results support the reported histopathological findings in livers of mice from this study and indicate that the effects of HFPO-DA are mediated through rodent-specific PPARα signaling mechanisms regardless of reproductive status in mice.

Chronic exposure to high-density polyethylene microplastic through feeding alters the nutrient metabolism of juvenile yellow perch (Perca flavescens)

Microplastics are emergent contaminants threatening aquatic organisms including aquacultured fish. This study investigated the effects of high-density polyethylene (HDPE, 100 to 125 μm) on yellow perch (Perca flavescens) based on integrative evaluation including growth performance, nutritional status, nutrient metabolism, fish health, and gut microbial community. Five test diets (0, 1, 2, 4, or 8 g HDPE/100 g diet) containing 41% protein and 10.5% lipid were fed to juvenile perch (average body weight, 25.9 ± 0.2 g; n = 15) at a feeding rate of 1.5% to 2.0% body weight daily. The feeding trial was conducted in a flow-through water system for 9 wk with 3 tanks per treatment and 15 yellow perch per tank. No mortality or HDPE accumulation in the fish was found in any treatments. Weight gain and condition factor of fish were not significantly impacted by HDPE (P > 0.05). Compared to the control group, fish fed the 8% HDPE diet had significantly decreased levels of protein and ash (P < 0.05). In response to the increasing levels of HDPE exposure, the hepatosomatic index value, hepatocyte size, and liver glycogen level were increased, but lipid content was reduced in the liver tissues. Compared to the control treatment, fish fed the 8% HDPE diet had significant accumulations of total bile acids and different metabolism pathways such as bile acid biosynthesis, pyruvate metabolism, and carnitine synthesis. Significant enterocyte necrosis was documented in the foregut of fish fed the 2% or 8% HDPE diet; and significant cell sloughing was observed in the midgut and hindgut of fish fed the 8% HDPE diet. Fish fed the 2% HDPE diet harbored different microbiota communities compared to the control fish. This study demonstrates that HDPE ranging from 100 to 125 μm in feed can be evacuated by yellow perch with no impact on growth. However, dietary exposure to HDPE decreased whole fish nutrition quality, altered nutrient metabolism and the intestinal histopathology as well as microbiota community of yellow perch. The results indicate that extended exposure may pose a risk to fish health and jeopardize the nutrition quality of aquacultured end product. This hypothesis remains to be investigated further.

Molecular characterization, antiviral activity, and UV-B damage responses of Caspase-9 from Amphiprion clarkii

Apoptosis plays a vital role in maintaining cellular homeostasis in multicellular organisms. Caspase-9 (casp-9) is one of the major initiator caspases that induces apoptosis by activating downstream intrinsic apoptosis pathway genes. Here, we isolated the cDNA sequence (1992 bp) of caspase-9 from Amphiprion clarkii (Accasp-9) that consists of a 1305 bp coding region and encodes a 434 aa protein. In silico analysis showed that Accasp-9 has a theoretical isoelectric point of 5.81 and a molecular weight of 48.45 kDa. Multiple sequence alignment revealed that the CARD domain is located at the N-terminus, whereas the large P-20 and small P-10 domains are located at the C-terminus. Moreover, a highly conserved pentapeptide active site (²⁹⁶QACGG³⁰¹), as well as histidine and cysteine active sites, are also retained at the C-terminus. In phylogenetic analysis, Accasp-9 formed a clade with casp-9 from different species, distinct from other caspases. Accasp-9 was highly expressed in the gill and intestine compared with other tissues analyzed in healthy A. clarkii. Accasp-9 expression was significantly elevated in the blood after stimulation with Vibrio harveyi and polyinosinic:polycytidylic acid (poly I:C; 12-48 h), but not with lipopolysaccharide. The nucleoprotein expression of the viral hemorrhagic septicemia virus was significantly reduced in Accasp-9 overexpressed fathead minnow (FHM) cells compared with that in the control. In addition, other in vitro assays revealed that cell apoptosis was significantly elevated in poly I:C and UV-B-treated Accasp-9 transfected FHM cells. However, H^248P or C^298S mutated Accasp-9 significantly reduced apoptosis in UV-B irradiated cells. Collectively, our results show that Accasp-9 might play a defensive role against invading pathogens and UV-B radiation and H²⁴⁸ and C²⁹⁸ active residues are significantly involved in apoptosis in teleosts.

Roles and Mechanisms of Regulated Necrosis in Corneal Diseases: Progress and Perspectives

Regulated necrosis is defined as cell death characterized by loss of the cell membrane integrity and release of the cytoplasmic content. It contributes to the development and progression of some diseases, including ischemic stroke injury, liver diseases, hypertension, and cancer. Various forms of regulated necrosis, particularly pyroptosis, necroptosis, and ferroptosis, have been implicated in the pathogenesis of corneal disease. Regulated necrosis of corneal cells enhances inflammatory reactions in the adjacent corneal tissues, leading to recurrence and aggravation of corneal disease. In this review, we summarize the molecular mechanisms of pyroptosis, necroptosis, and ferroptosis in corneal diseases and discuss the roles of regulated necrosis in inflammation regulation, tissue repair, and corneal disease outcomes.

Paradoxical roles of caspase-3 in regulating cell survival, proliferation, and tumorigenesis

Caspase-3 is a widely expressed member of a conserved family of proteins, generally recognized for their activated proteolytic roles in the execution of apoptosis in cells responding to specific extrinsic or intrinsic inducers of this mode of cell death. However, accumulating evidence indicates that caspase-3 also plays key roles in regulating the growth and homeostatic maintenance of both normal and malignant cells and tissues in multicellular organisms. Given that yeast possess an ancestral caspase-like gene suggests that the caspase-3 protein may have acquired different functions later during evolution to better meet the needs of more complex multicellular organisms, but without necessarily losing all of the functions of its ancestral yeast precursor. This review provides an update on what has been learned about these interesting dichotomous roles of caspase-3, their evolution, and their potential relevance to malignant as well as normal cell biology.

BRCC36 promotes intestinal mucosal barrier injury caused by BMP2 after ischemia reperfusion via inhibiting PPARγ signaling

As one of the most common pathological changes in trauma and surgery practice, intestinal ischemia-reperfusion (I/R) injury is regarded as a major precipitating factor in the occurrence and development of fatal diseases. BRCA1-BRCA2-containing complex subunit 36 (BRCC36), a deubiquitinase, has been proved important in a variety of pathophysiological processes such as DNA repair, cell cycle regulation, tumorigenesis, and inflammatory response. However, the effect of BRCC36 on intestinal mucosal barrier injury after I/R has not been fully elucidated. Our research found that BRCC36 aggravated intestinal mucosal barrier injury caused by bone morphogenetic protein 2 after I/R by downregulating peroxisome proliferator-activated receptor-γ (PPARγ) signaling. These results suggested that BRCC36/PPARγ axis might serve as a potential therapeutic target for preventing intestinal mucosal barrier injury after I/R.

Cadmium exposure triggers oxidative stress, necroptosis, Th1/Th2 imbalance and promotes inflammation through the TNF-α/NF-κB pathway in swine small intestine

Cadmium (Cd) is a toxic environmental pollutant and induces toxic effects to organism. Nevertheless, the mechanism of Cd-induced toxicity in swine remains obscure. To explore this, 10 healthy 6-week-old weaned swine were placed into two groups stochastically, the Cd group was treated with a commercial diet containing 20 mg/kg Cd for 40 days. The results of histopathological and ultrastructural observations showed typical necrosis features and inflammatory cell infiltration in Cd group. Excessive Cd suppressed T-AOC and SOD activities, increased MDA content and ROS levels. Cd diet elevated the expression of RIPK1, RIPK3, and MLKL to activate the RIPK3-dependent necroptosis pathway. Results of Th1 and Th2 cytokines indicated that the levels of IL-4, IL-6 and IL10 was increased, while the level of IFN-γ was decreased, illustrating Th1/Th2 immune imbalance leads to aggravate inflammatory responses. Cd activated the TNF-α/NF-κB pathway and induced inflammatory responses via increasing the expression of HO-1, IL-1β, iNOS, COX2. Heat shock proteins were notably elevated in response to inflammatory reactions. And these effects were inhibited by necrostatin-1 (Nec-1) and N-acetyl-cysteine (NAC). Altogether, these data demonstrated that Cd induced necroptosis and inflammation to aggravate small intestine injury in swine by increasing the excessive accumulation of ROS and imbalanced Th1/Th2, respectively.

NLRP3/caspase-1/GSDMD-mediated pyroptosis exerts a crucial role in astrocyte pathological injury in mouse model of depression

Emerging evidence suggests that astrocyte loss is one of the most important pathological features in the hippocampus of patients with major depressive disorder (MDD) and depressive mice. Pyroptosis is a recently discovered form of programmed cell death depending on Caspase-gasdermin D (Casp-GSDMD), which is involved in multiple neuropsychiatric diseases. However, the involvement of pyroptosis in the onset of MDD and glial pathological injury remains obscure. Here, we observed that depressive mice showed astrocytic pyroptosis, which was responsible for astrocyte loss, and selective serotonin reuptake inhibitor (SSRI) treatment could attenuate the pyroptosis induced by the chronic mild stress (CMS) model. Genetic KO of GSDMD, Casp-1, and astrocytic NOD-like receptor protein 3 (NLRP3) inflammasome in mice alleviated depression-like behaviors and inhibited the pyroptosis-associated protein expression. In contrast, overexpression of astrocytic GSDMD-N-terminal domain (GSDMD-N) in the hippocampus could abolish the improvement of behavioral alterations in GSDMD-deficient mice. This work illustrates that targeting the NLRP3/Casp-1/GSDMD-mediated pyroptosis may provide potential therapeutic benefits to stress-related astrocyte loss in the pathogenesis of depression.

Nanostructured systems increase the in vitro cytotoxic effect of bullfrog oil in human melanoma cells (A2058)

The aim of this work was to investigate the in vitro cytotoxic effect of previously developed nanocapsules, nanoemulsion, and microemulsion based on bullfrog oil (BFO) against human melanoma cells (A2058). The nanosystems were produced as described in previous studies and characterized according to droplet/particle distribution and zeta potential. The biocompatibility was evaluated by the determination of the hemolytic potential against human erythrocytes. The cytotoxicity assessment was based on MTT and cell death assays, determination of Reactive Oxygen Species (ROS) levels, and cell uptake. The nanosystems were successfully reproduced and showed hemolytic potential smaller than 10% at all oil concentrations (50 and 100 µg.mL^-1) (p < 0.05). The MTT assay revealed that the nanosystems decreased the mitochondrial activity up to 92 ± 2% (p < 0.05). The study showed that the free BFO induced cell apoptosis, while all the nanostructured systems caused cell death by necrosis associated with a ROS overproduction. This can be related to the increased ability of the nanostructured systems to deliver the BFO across all cellular compartments (membrane, cytoplasm, and nucleus). Finally, these results elucidate the in vitro BFO nanosystems cytotoxic effect against human melanoma cells (A2058), revealing the emulsified ones as the most cytotoxic systems. Overall, the findings suggest that the safety and antineoplastic activity of these systems can be further investigated by in vivo studies.

NETosis in ischemic/reperfusion injuries: An organ-based review

Neutrophil extracellular trap (NETosis), the web-like structures induced by neutrophil death, is an important inflammatory mechanism of the immune system leading to reactive oxygen species production/coagulopathy, endothelial dysfunction, atherosclerosis, and ischemia. NETosis exerts its role through different mechanisms such as triggering Toll-like receptors, inflammatory cytokines, platelet aggregation, neutrophil activation/infiltration, and vascular impairment. NETosis plays a key role in the prognosis of coronary artery disease, ischemic injury of kidney, lung, gastrointestinal tract and skeletal muscles. In this review, we explored the molecular mechanisms involved in NETosis, and ischemic/reperfusion injuries in body organs.

Advances in the regulation of natural polysaccharides on human health: The role of apoptosis/autophagy pathway

Due to the multiple biological activities of polysaccharides, their great potential as "natural drugs" for many diseases has been the subject of continuous exploration in the field of food and nutrition. Apoptosis and autophagy play a key role in mammalian growth, development and maintenance of cellular homeostasis. Recent studies suggest that apoptosis/autophagy may be the key regulatory target for the beneficial effects of polysaccharides. However, the regulation of apoptosis and autophagy by polysaccharides is not consistent in different disease models. Therefore, this review outlined the relationship between apoptosis/autophagy and some common human diseases, then discussed the role of apoptosis/autophagy pathway in the regulation of human health by polysaccharides, Furthermore, the application of visualization, imaging and multi-omics techniques was proposed in the future trend. The present review may be beneficial to accelerate our understanding of the anti-disease mechanisms of polysaccharides, and promote the development and utilization of polysaccharides.

Arbutin Ameliorates Murine Colitis by Inhibiting JAK2 Signaling Pathway

Background and objective: Abnormal activation of Janus kinase 2 (JAK2) promotes the pathogenesis and progress of inflammatory bowel disease (IBD) by stimulating the cytokine traffic. Based on docking studies, arbutin, a natural product extracted from a traditional medicinal plant bearberry, was found to bind to JAK2. The study aimed to investigate the effects and mechanisms of regulating JAK2 by arbutin on colitis in mice.

Methods: A mice colitis model was established to mimic human IBD. The mice freely drank water containing dextran sulfate sodium. Inflammation in epithelial (IEC6) and immune (RAW264.7) cells was analyzed following treatment with lipopolysaccharides (LPS).

Results: Colitis symptoms, including body weight loss, increased disease activity index, and increased colon weight/length ratio, were significantly alleviated by arbutin. Mediators of colonic pro-inflammatory cytokines as well as apoptosis markers in colitis were suppressed by the glycoside. High expression of phosphorylated JAK2 in colitis was significantly reversed by arbutin. The effects of arbutin treatment on colitis were considerably inhibited by the JAK2 inhibitor AG490. LPS-induced inflammatory responses were also suppressed by arbutin, which was notably inhibited by the JAK2 inhibitor AG490.

Conclusion: The findings obtained herein suggest the protective role of arbutin and provide novel insights into alternative colitis treatments, which involve inhibition of the JAK2 signaling pathway.

Jejunal Transcriptomic Profiling for Differences in Feed Conversion Ratio in Slow-Growing Chickens

Simple Summary

The slow-growing Korat chicken (KR) is economically attractive, as KR meat has a high selling price and has thus been used in Thailand to support smallholder farmers. However, low feed efficiency in KR stockbreeding makes the product less competitive and improving KR feed efficiency is central to increasing KR profitability. Using RNA sequencing, we compared the jejunal transcriptomic profiles of low- and high-feed conversion ratio (FCR) KR chickens, to identify FCR-related transcriptional variation and biological pathways. Gene Ontology and Kyoto Encyclopedia of Gene and Genome analysis revealed that the main pathways involved in KR FCR variation are related to immune response, glutathione metabolism, vitamin transport and metabolism, lipid metabolism, and neuronal and cardiac maturation, development, and growth. This is the first study to investigate, in the jejunum, the molecular genetic mechanisms affecting the FCR of slow-growing chickens. These findings will be useful in line-breeding programs to improve feed efficiency and profitability in slow-growing chicken stockbreeding.

Abstract

Improving feed efficiency is an important breeding target for the poultry industry; to achieve this, it is necessary to understand the molecular basis of feed efficiency. We compared the jejunal transcriptomes of low- and high-feed conversion ratio (FCR) slow-growing Korat chickens (KRs). Using an original sample of 75 isolated 10-week-old KR males, we took jejunal samples from six individuals in two groups: those with extremely low FCR (n = 3; FCR = 1.93 ± 0.05) and those with extremely high FCR (n = 3; FCR = 3.29 ± 0.06). Jejunal transcriptome profiling via RNA sequencing revealed 56 genes that were differentially expressed (p < 0.01, FC > 2): 31 were upregulated, and 25 were downregulated, in the low-FCR group relative to the high-FCR group. Functional annotation revealed that these differentially expressed genes were enriched in biological processes related to immune response, glutathione metabolism, vitamin transport and metabolism, lipid metabolism, and neuronal and cardiac maturation, development, and growth, suggesting that these are important mechanisms governing jejunal feed conversion. These findings provide an important molecular basis for future breeding strategies to improve slow-growing chicken feed efficiency.

Design, Synthesis, and Biological Evaluation of a Novel Aminothiol Compound as Potential Radioprotector

The risk of radiation damage has increased with the rapid development of nuclear technology and radiotherapy. Hence, research on radioprotective agents is of utmost importance. In the present study, a novel aminothiol compound 12, containing a linear alkylamino backbone and three terminal thiols, was synthesized. Owing to the appropriate capped groups in the chains, it has an improved permeability and oral bioavailability compared to other radioprotective agents. Oral administration of compound 12 improved the survival of mice that received lethal doses of γ-irradiation. Experimental results demonstrated that compound 12 not only mitigated total body irradiation-induced hematopoietic injury by increasing the frequencies of hematopoietic stem and progenitor cells but also prevented abdominal irradiation-induced intestinal injury by increasing the survival of Lgr5⁺ intestinal cells, lysozyme⁺ Paneth cells, and Ki67⁺ cells. In addition, compound 12 decreased oxidative stress by upregulating the expression of Nrf2 and NQO1 and downregulating the expression of NOX1. Further, compound 12 inhibited γ-irradiation-induced DNA damage and alleviated G2/M phase arrest. Moreover, compound 12 decreased the levels of p53 and Bax and increased the level of Bcl-2, demonstrating that it may suppress radiation-induced apoptosis via the p53 pathway. These results indicate that compound 12 has the possibility of preventing radiation injury and can be a potential radioprotector for clinical applications.

Ketogenesis alleviates TNFα-induced apoptosis and inflammatory responses in intestinal cells

The disturbance of strictly regulated self-regeneration in mammalian intestinal epithelium is associated with various intestinal disorders, particularly inflammatory bowel diseases (IBDs). TNFα, which plays a critical role in the pathogenesis of IBDs, has been reported to inhibit production of ketone bodies such as β-hydroxybutyrate (βHB). However, the role of ketogenesis in the TNFα-mediated pathological process is not entirely known. Here, we showed the regulation and role of HMGCS2, the rate-limiting enzyme of ketogenesis, in TNFα-induced apoptotic and inflammatory responses in intestinal epithelial cells. Treatment with TNFα dose-dependently decreased protein and mRNA expression of HMGCS2 and its product, βHB production in human colon cancer cell lines HT29 and Caco2 cells and mouse small intestinal organoids. Moreover, the repressed level of HMGCS2 protein was found in intestinal epithelium of IBD patients with Crohn's disease and ulcerative colitis as compared with normal tissues. Furthermore, knockdown of HMGCS2 enhanced and in contrast, HMGCS2 overexpression attenuated, the TNFα-induced apoptosis and expression of pro-inflammatory chemokines (CXCL1-3) in HT29, Caco2 cells and DLD1 cells, respectively. Treatment with βHB or rosiglitazone, an agonist of PPARγ, which increases ketogenesis, attenuated TNFα-induced apoptosis in the intestinal epithelial cells. Finally, HMGCS2 knockdown enhanced TNFα-induced reactive oxygen species (ROS) generation. In addition, hydrogen peroxide, the major ROS contributing to intestine injury, decreased HMGCS2 expression and βHB production in the intestinal cells and mouse organoids. Our findings demonstrate that increased ketogenesis attenuates TNFα-induced apoptosis and inflammation in intestinal cells, suggesting a protective role for ketogenesis in TNFα-induced intestinal pathologies.

The expression of RIPK3 is associated with cell turnover of gastric mucosa in the mouse and human stomach

Necroptosis is a novel manner of programmed cell death and important for tissue development, homeostasis, damage, and repair. Activation of receptor-interacting protein kinase 3 (RIPK3), a key member of receptor-interacting protein family in contributing significantly to necroptosis, in tissues is a hallmark of cells dying by necroptosis. However, there are few studies that examine the expression of RIPK3 in the glandular cells of stomachs under physiological condition. We have therefore conducted this study to immunohistochemically characterize the key element of necroptosis, RIPK3, in the mouse and human stomach. Results showed that RIPK3 positive cells could be observed in the surface mucosal cells, granular cells, and lamina propria cells in both mouse and human stomach tissues. Ratios of PCNA/RIPK3 positive cells in the glandular cells were ~ 2.1 in mouse and ~ 4.15 in human sections respectively. Morphological and double immunofluorescence analysis confirmed that these RIPK3 positive cells were mucous, parietal and lamina propria cells. Our results indicate that the expression of RIPK3 in different cell types might contribute to cell turnover of gastric mucosa in the mouse and human stomach under physiological condition.

Effect of yeast cell wall supplementation on intestinal integrity, digestive enzyme activity and immune traits of broilers

1. The protective layer formed by intestinal epithelial cells acts as a barrier preventing the adhesion of pathogenic bacteria, aids digestion and passage of nutrients and reduces damage caused from toxins on the gastrointestinal tract. This study was conducted to investigate the effects of a yeast cell wall-based product (YCW), on broiler intestinal integrity, digestive enzyme capacity and immune function.2. A 35-d trial involving 246, one-d-of-hatch male broiler chickens was carried out at a trial facility at Agri-Food Biosciences Institute (AFBI, Belfast, UK). Birds were randomly allocated into 6 pens at day of hatch (41 birds/pen; 123 birds/group). Pens were divided into two groups: (1) basal diet and (2) basal diet that incorporated YCW at the manufacturers' recommended inclusion levels (Alltech Inc., Lexington, Kentucky, USA).3. In this study, YCW supplementation affected broiler intestinal morphology resulting in greater crypt depth, villus height and surface area, goblet cell density and mucus layer thickness and lower muscularis mucosae thickness. The digestive enzymes, maltase, sucrase and alkaline phosphatase, were significantly higher in the YCW supplemented group compared to the control. The expression levels of pro-inflammatory cytokines, IL-1β, IL-12 and IL-18, were significantly lower as was necroptotic cell death in YCW supplemented birds.4. In conclusion, under the conditions of this study, YCW supplementation positively affected intestinal health parameters in broilers following 35-d supplementation.